Preface

Corrosion is a big problem globally and needs to be minimized to boost the economy. Corrosion is omnipresent in all metallic systems in all parts of the world. All systems used in engineering are subject to corrosion, which leads to their degradation, including systems used in clean energy, water supply, construction, transportation, food, commercial world, treatment plants, boilers, and storage tanks. Corrosion is part of our life from stents used in the heart, wires used in teeth, Mg/Ti implants in the body, to nuclear power plants. Due to its presence in industries and multidisciplinary areas, corrosion is one of the hot topics of research for young scientists and students who are placing their feet in the shoes of other professors and eminent scientists to find a suitable solution.

Corrosion is a big threat resulting in the loss of billions of dollars each year. This economic meltdown needs to be mitigated through proper and advanced techniques. Scientists and authors have come up with new techniques comprising of ceramics, polymers, glass, and other materials in line with the existing techniques. However, there is an ongoing demand to meet the environment regulations and produce low cost corrosion inhibitors and coatings. This book includes different sections with several chapters embedded in it. The sections include chapters on corrosion inhibitors, biological corrosion, implants, and general corrosion. All these chapters will serve the academicians, researchers, and industrialists to grasp deeper insights into the mechanism and mode of action of corrosion on different metals in various aggressive solutions.

**II**

**Chapter 7 117**

**Chapter 8 133**

Biocorrosion **143**

**Chapter 9 145**

**Chapter 10 155**

Spectroscopy in Oilfield Corrosion Monitoring and Inhibition

*by Michael Schorr, Benjamín Valdez, Margarita Stoytcheva* 

Kinetics and Structure Aspects of the Dissolution of Stainless Steels

Production of Hydroxyapatite on the Surface of Ti6Al7Nb Alloy

*by Elinor Nahum, Svetlana Lugovskoy and Alex Lugovskoy*

Biotribology of Mechanically and Laser Marked Biomaterial

*Jorge Humberto Luna-Domínguez and Ronaldo Câmara Cozza*

*by Ekemini Ituen, Lin Yuanhua, Ambrish Singh* 

*and Onyewuchi Akaranta*

in Phosphoric Acid

*and Roumen Zlatev*

as Compared to Ti6Al4V Alloy

*by Marcelo de Matos Macedo, Vikas Verma,* 

**Section 4**

**Dr. Ambrish Singh** Professor, School of New Energy and Materials, Southwest Petroleum University, Chengdu City, China

Section 1

Corrosion Inhibitor

**1**

Section 1 Corrosion Inhibitor

**Chapter 1**

**Abstract**

**1. Introduction**

required need.

**3**

*and Yuanhua Lin*

Corrosion Mitigation by Planar

*Ambrish Singh, Kashif R. Ansari, Dheeraj S. Chauhan,*

The corrosion has a considerable amount of impact on the economics of every nation, and ultimately it affects the GDP. In the present era, the challenge given by corrosion can be easily mitigated using organic compounds as corrosion inhibitor in different corrosive media. The important property of an inhibitor is the presence of the metal interacting with heteroatoms and a planar structure. In this regard, benzimidazoles (BI) with a fused bicyclic ring consisting of benzene and imidazole moiety in their structural framework making them a potential candidate for anticorrosion work. In addition to this, bezimidazole derivatives are classified as green inhibitor due to different kinds of biological activities. Their higher potency to mitigate corrosion is because of the planar molecular structure, nitrogen atom and sp2 hybridized carbon, which provide them an ability to strongly interact with the metal. The focus of this book chapter is to investigate briefly the anti-corrosion ability of benzimidazole (BI) and their derivatives as a potential corrosion inhibitor

Benzimidazole Derivatives

for various industrially useful metals in different aggressive media.

The costs and the aftermath of corrosion are enormous. There are so many reports identified, resulting in the death and injury of living beings due to the corrosion failure. The easily quantifiable costs are those associated with the repair and replacement of equipment. It is very much difficult to predict the exact loss associated with the corrosion especially when corrosion causes the production unit in the petroleum industry to shut down. The potential method to reduce the corrosion is using the organic compounds in the aggressive media for protecting the metals against corrosion. Among the numerous inhibitor groups, benzimidazole derivatives have gained a more practical application due to their environmentally benign nature, potential ability to strongly interact with the metal surface through the nitrogen atoms and easy methods to modify their molecular structure as per the

The benzo derivative of imidazole is referred to as benzimidazole. Although benzimidazole is the commonest name of the parent compound of the series, other names such as benzimidazole and 1,3-benzodiazole are often used. The main purpose of this book chapter is to introduce briefly the anti-corrosion ability of

**Keywords:** benzimidazole, corrosion, inhibitor

*Mumtaz A. Quraishi, Savas Kaya, Hua Yu*

#### **Chapter 1**

## Corrosion Mitigation by Planar Benzimidazole Derivatives

*Ambrish Singh, Kashif R. Ansari, Dheeraj S. Chauhan, Mumtaz A. Quraishi, Savas Kaya, Hua Yu and Yuanhua Lin*

#### **Abstract**

The corrosion has a considerable amount of impact on the economics of every nation, and ultimately it affects the GDP. In the present era, the challenge given by corrosion can be easily mitigated using organic compounds as corrosion inhibitor in different corrosive media. The important property of an inhibitor is the presence of the metal interacting with heteroatoms and a planar structure. In this regard, benzimidazoles (BI) with a fused bicyclic ring consisting of benzene and imidazole moiety in their structural framework making them a potential candidate for anticorrosion work. In addition to this, bezimidazole derivatives are classified as green inhibitor due to different kinds of biological activities. Their higher potency to mitigate corrosion is because of the planar molecular structure, nitrogen atom and sp2 hybridized carbon, which provide them an ability to strongly interact with the metal. The focus of this book chapter is to investigate briefly the anti-corrosion ability of benzimidazole (BI) and their derivatives as a potential corrosion inhibitor for various industrially useful metals in different aggressive media.

**Keywords:** benzimidazole, corrosion, inhibitor

#### **1. Introduction**

The costs and the aftermath of corrosion are enormous. There are so many reports identified, resulting in the death and injury of living beings due to the corrosion failure. The easily quantifiable costs are those associated with the repair and replacement of equipment. It is very much difficult to predict the exact loss associated with the corrosion especially when corrosion causes the production unit in the petroleum industry to shut down. The potential method to reduce the corrosion is using the organic compounds in the aggressive media for protecting the metals against corrosion. Among the numerous inhibitor groups, benzimidazole derivatives have gained a more practical application due to their environmentally benign nature, potential ability to strongly interact with the metal surface through the nitrogen atoms and easy methods to modify their molecular structure as per the required need.

The benzo derivative of imidazole is referred to as benzimidazole. Although benzimidazole is the commonest name of the parent compound of the series, other names such as benzimidazole and 1,3-benzodiazole are often used. The main purpose of this book chapter is to introduce briefly the anti-corrosion ability of

benzimidazole and their derivatives as a potential corrosion inhibitor for the various industrially useful metals in different aggressive media.

#### **1.1 A brief overview on biological activities**

The molecular structure of benzimidazole arises by fusing the benzene and imidazole rings. It generates a class of bicyclic compounds which have a wide range of biological and pharmacological activities (**Figure 1**).

The molecular structures of some benzimidazole containing nucleus compounds, which are commonly used for various therapeutic applications, are presented in **Figure 2**: (1) benoxaprofen analog (anti-inflammatory), (2) pantoprazole (proton pump inhibitor), (3) candesartan (antihypertensive), (4) albendazole (anthelmintics/antimicrobial), (5) mebendazole (anthelmintics), (6) bilastine (antihistaminic), (7) carbendazim (antifungal), (8) bendamustine (antitumor) and (9) astemizole (antihistaminic) [1].

#### **1.2 Molecular structure**

The general molecular structure consists of a bicyclic heteroatomic structure with two nitrogen atoms (**Figure 3**).

The benzimidazole derivatives have different kinds of extensive coupling constant, which leads to generate coupling with strong force constants [2].

> Benzimidazole derivatives have a greater affinity to produce a variation of chemical species because of the high force constant, and this is a remarkable characteristic of the benzimidazole. The analysis of vibrational property of benzimidazole derivatives is difficult due to the presence of extensive coupling in their molecular structure [3], although scientists were successful to analyse the vibrational properties of simple benzimidazole derivatives by applying density functional theory (DFT).

The synthesis of benzimidazole is very important with respect to their varying potential pharmacological activities. Thus, a unique attention is required to fulfil this process. In literature, various methods are given using different kinds of cata-

Azarifar et al. [4], synthesized benzimidazole derivatives by condensation of o-phenylenediamine promoted by acetic acid under microwave. They concluded that a mild, manipulatable procedure, eco-friendly and green aspects avoiding hazardous solvents, shorter reaction times and high yields of the products are the

**1.3 Synthesis**

**5**

**Figure 2.**

**Figure 3.**

*Therapeutic applications of benzimidazole derivatives.*

*Corrosion Mitigation by Planar Benzimidazole Derivatives*

*DOI: http://dx.doi.org/10.5772/intechopen.92276*

lyst. Few of them are as follows:

*Molecular structure of benzimidazole.*

advantages of this method.

**Figure 1.** *Biological activities of benzimidazole.*

*Corrosion Mitigation by Planar Benzimidazole Derivatives DOI: http://dx.doi.org/10.5772/intechopen.92276*

benzimidazole and their derivatives as a potential corrosion inhibitor for the various

The molecular structure of benzimidazole arises by fusing the benzene and imidazole rings. It generates a class of bicyclic compounds which have a wide range

The molecular structures of some benzimidazole containing nucleus compounds, which are commonly used for various therapeutic applications, are presented in **Figure 2**: (1) benoxaprofen analog (anti-inflammatory),

(2) pantoprazole (proton pump inhibitor), (3) candesartan (antihypertensive), (4) albendazole (anthelmintics/antimicrobial), (5) mebendazole (anthelmintics), (6) bilastine (antihistaminic), (7) carbendazim (antifungal), (8) bendamustine

The general molecular structure consists of a bicyclic heteroatomic structure

The benzimidazole derivatives have different kinds of extensive coupling con-

stant, which leads to generate coupling with strong force constants [2].

industrially useful metals in different aggressive media.

of biological and pharmacological activities (**Figure 1**).

(antitumor) and (9) astemizole (antihistaminic) [1].

**1.2 Molecular structure**

*Corrosion*

**Figure 1.**

**4**

*Biological activities of benzimidazole.*

with two nitrogen atoms (**Figure 3**).

**1.1 A brief overview on biological activities**

**Figure 2.** *Therapeutic applications of benzimidazole derivatives.*

Benzimidazole derivatives have a greater affinity to produce a variation of chemical species because of the high force constant, and this is a remarkable characteristic of the benzimidazole. The analysis of vibrational property of benzimidazole derivatives is difficult due to the presence of extensive coupling in their molecular structure [3], although scientists were successful to analyse the vibrational properties of simple benzimidazole derivatives by applying density functional theory (DFT).

#### **1.3 Synthesis**

The synthesis of benzimidazole is very important with respect to their varying potential pharmacological activities. Thus, a unique attention is required to fulfil this process. In literature, various methods are given using different kinds of catalyst. Few of them are as follows:

Azarifar et al. [4], synthesized benzimidazole derivatives by condensation of o-phenylenediamine promoted by acetic acid under microwave. They concluded that a mild, manipulatable procedure, eco-friendly and green aspects avoiding hazardous solvents, shorter reaction times and high yields of the products are the advantages of this method.

Shaikh et al. [5] have efficiently synthesized benzimidazoles in high yields by treatment of 1,2-diamine with aldehydes using the metal coordinate complex K4[Fe (CN)6] as a catalysis.

Srinivasulu et al. synthesized benzimidazole derivatives using zinc triflate as an efficient catalyst in a one-pot synthesis of 2-substituted benzimidazole derivatives from o-phenylenediamine and substituted aldehydes in ethanol solvent at reflux temperature. They concluded that zinc triflate was found to be an efficient catalyst for the formation of benzimidazole from aldehydes and o-phenylenediamine [10].

*Corrosion Mitigation by Planar Benzimidazole Derivatives*

*DOI: http://dx.doi.org/10.5772/intechopen.92276*

Patil et al. [11] have shown that benzimidazole derivatives have been synthesized by reacting substituted o-phenylenediamine with aldehyde derivatives using a

Karimi-Jaberi et al. [12] had synthesized 2-substituted benzimidazoles in a onepot reaction from o-phenylenediamine and aldehydes in the presence of boric acid

catalytic amount of zinc acetate at room temperature with excellent yields.

Kidwai et al. [13] synthesized benzimidazole derivatives from o-

benzimidazoles in good yields with little catalyst loading.

phenylenediamine and aldehydes in PEG as a solvent with ceric ammonium nitrate (CAN) as a catalyst. This method provides a novel route for the synthesis of

in water at room temperature.

**7**

Vaidehi et al. [6] had synthesized a set of 2-substituted benzimidazoles successfully by condensation of o-phenylenediamine with substituted acids in the presence of ring closing agents like polyphosphoric acid/HCl. The present work has demonstrated the use of a simple cyclocondensation method and ring closing agents for synthesis of 2-substituted benzimidazoles.

Rekha et al. [7] studied the catalytic activity of alumina, zirconia, manganese oxide/alumina and manganese oxide/zirconia in the condensation reaction between o-phenylenediamine and an aldehyde or a ketone to synthesize 2-substituted benzimidazoles and 1,5-disubstituted benzodiazepines, respectively.

Chunxia et al. [8] have developed a straightforward method for the synthesis of the benzimidazole ring system through a carbon-nitrogen cross-coupling reaction in the presence of K2CO3 in water at 100°C for 30 h; the intermolecular cyclization of N-(2-iodoaryl) benzamidine provides benzimidazole derivatives in moderate to high yields.

Kathirvelan et al. [9] synthesized various 2-substituted benzimidazoles in moderate to good yields in a one-pot reaction by condensation of o-phenylenediamine and an aldehyde in the presence of ammonium chloride as a catalyst at 80–90°C.

*Corrosion Mitigation by Planar Benzimidazole Derivatives DOI: http://dx.doi.org/10.5772/intechopen.92276*

Shaikh et al. [5] have efficiently synthesized benzimidazoles in high yields by treatment of 1,2-diamine with aldehydes using the metal coordinate complex K4[Fe

Vaidehi et al. [6] had synthesized a set of 2-substituted benzimidazoles successfully by condensation of o-phenylenediamine with substituted acids in the presence of ring closing agents like polyphosphoric acid/HCl. The present work has demonstrated the use of a simple cyclocondensation method and ring closing agents for

Rekha et al. [7] studied the catalytic activity of alumina, zirconia, manganese oxide/alumina and manganese oxide/zirconia in the condensation reaction between o-phenylenediamine and an aldehyde or a ketone to synthesize 2-substituted benz-

Chunxia et al. [8] have developed a straightforward method for the synthesis of the benzimidazole ring system through a carbon-nitrogen cross-coupling reaction in the presence of K2CO3 in water at 100°C for 30 h; the intermolecular cyclization of N-(2-iodoaryl) benzamidine provides benzimidazole derivatives in moderate to

Kathirvelan et al. [9] synthesized various 2-substituted benzimidazoles

o-phenylenediamine and an aldehyde in the presence of ammonium chloride

in moderate to good yields in a one-pot reaction by condensation of

imidazoles and 1,5-disubstituted benzodiazepines, respectively.

(CN)6] as a catalysis.

*Corrosion*

high yields.

as a catalyst at 80–90°C.

**6**

synthesis of 2-substituted benzimidazoles.

Srinivasulu et al. synthesized benzimidazole derivatives using zinc triflate as an efficient catalyst in a one-pot synthesis of 2-substituted benzimidazole derivatives from o-phenylenediamine and substituted aldehydes in ethanol solvent at reflux temperature. They concluded that zinc triflate was found to be an efficient catalyst for the formation of benzimidazole from aldehydes and o-phenylenediamine [10].

Patil et al. [11] have shown that benzimidazole derivatives have been synthesized by reacting substituted o-phenylenediamine with aldehyde derivatives using a catalytic amount of zinc acetate at room temperature with excellent yields.

Karimi-Jaberi et al. [12] had synthesized 2-substituted benzimidazoles in a onepot reaction from o-phenylenediamine and aldehydes in the presence of boric acid in water at room temperature.

Kidwai et al. [13] synthesized benzimidazole derivatives from ophenylenediamine and aldehydes in PEG as a solvent with ceric ammonium nitrate (CAN) as a catalyst. This method provides a novel route for the synthesis of benzimidazoles in good yields with little catalyst loading.

Khunt et al. [14] have synthesized the benzimidazole by reacting ophenylenediamine with several aldehydes using a green solvent PEG400 and got good yields.

#### **2. Corrosion inhibition by benzimidazole derivatives**

The inhibition ability of the organic compounds containing heteroatoms depends upon the rate of the molecular adsorption at the metal/solution interface which in turn depends upon the molecular structure/symmetry and charge density presenting on the inhibitor molecules [15]. Benzimidazoles are very good corrosion inhibitors because of their unique molecular structure and solubility in aqueous media. As we have seen in **Figure 3**, the molecular structure of benzimidazole has an aromatic property due to the presence of the fused six-membered benzene ring with the imidazole ring. The presence of planar benzene ring with sp2 hybridized carbon atoms and lone pair of electrons presenting on the nitrogen atoms of the imidazole ring makes the whole molecular system as an anchoring site for molecular adsorption at the metal surface [16, 17].

#### **2.1 Metal protection by benzimidazole in aqueous media**

Benzimidazole and its derivatives prevail themselves as potential corrosion inhibitor candidates. They prove the ability to reduce the corrosion phenomenon in aqueous media for various metals like mild steel, copper, brass and zinc. In this chapter, I would like to emphasize only on these metals. The molecular structures of benzimidazole derivatives studied in this book chapter are tabulated in **Table 1**.

#### *2.1.1 Experimental results*

Ramya et al. [18] have studied the synergistic hydrogen-bonded interaction of alkyl benzimidazole derivatives (2-MBI, 2-EBI, 2-PBI), and 1,2,3-benzotrizole (BTZ) and its corrosion protection properties on mild steel in hydrochloric acid at different temperatures have been studied using polarization, EIS, adsorption, surface studies and computational methods. They observed that benzimidazole derivatives and BTZ molecules are effective inhibitors and their inhibition efficiency increases when these two inhibitors are used in combination.

In 2011 Guadalupe et al. [19] analysed the corrosion inhibition properties of BBED via electrochemical (polarization curves and electrochemical impedance spectroscopy) and DFT techniques. Electrochemical impedance data demonstrate that the interface charge capacitance of the electrode with the BBED solution affects the time of charge/discharge of the interface, facilitating the formation of adsorption layer over the iron surface. They also estimated the fractal dimension of the electrode surface in order to understand the nature of the electrode surface. DFT results clearly show that BBED possess corrosion inhibition properties by having a delocalization region (N1]C1]N2) in the benzimidazole ring that gives up its p

**Structure**

**9**

**Metal/medium** Mild steel/1 M HCl Carbon steel/1 M HCl Mild steel/0.1–1 M HCl

[20]

[19]

*DOI: http://dx.doi.org/10.5772/intechopen.92276*

*Corrosion Mitigation by Planar Benzimidazole Derivatives*

**Reference**

[18]

#### *Corrosion Mitigation by Planar Benzimidazole Derivatives DOI: http://dx.doi.org/10.5772/intechopen.92276*

Khunt et al. [14] have synthesized the benzimidazole by reacting ophenylenediamine with several aldehydes using a green solvent PEG400 and got

**2. Corrosion inhibition by benzimidazole derivatives**

**2.1 Metal protection by benzimidazole in aqueous media**

increases when these two inhibitors are used in combination.

adsorption at the metal surface [16, 17].

*2.1.1 Experimental results*

**8**

The inhibition ability of the organic compounds containing heteroatoms depends upon the rate of the molecular adsorption at the metal/solution interface which in turn depends upon the molecular structure/symmetry and charge density presenting on the inhibitor molecules [15]. Benzimidazoles are very good corrosion inhibitors because of their unique molecular structure and solubility in aqueous media. As we have seen in **Figure 3**, the molecular structure of benzimidazole has an aromatic property due to the presence of the fused six-membered benzene ring with the imidazole ring. The presence of planar benzene ring with sp2 hybridized carbon atoms and lone pair of electrons presenting on the nitrogen atoms of the imidazole ring makes the whole molecular system as an anchoring site for molecular

Benzimidazole and its derivatives prevail themselves as potential corrosion inhibitor candidates. They prove the ability to reduce the corrosion phenomenon in aqueous media for various metals like mild steel, copper, brass and zinc. In this chapter, I would like to emphasize only on these metals. The molecular structures of benzimidazole derivatives studied in this book chapter are tabulated in **Table 1**.

Ramya et al. [18] have studied the synergistic hydrogen-bonded interaction of alkyl benzimidazole derivatives (2-MBI, 2-EBI, 2-PBI), and 1,2,3-benzotrizole (BTZ) and its corrosion protection properties on mild steel in hydrochloric acid at different temperatures have been studied using polarization, EIS, adsorption, surface studies and computational methods. They observed that benzimidazole derivatives and BTZ molecules are effective inhibitors and their inhibition efficiency

In 2011 Guadalupe et al. [19] analysed the corrosion inhibition properties of BBED via electrochemical (polarization curves and electrochemical impedance spectroscopy) and DFT techniques. Electrochemical impedance data demonstrate that the interface charge capacitance of the electrode with the BBED solution affects the time of charge/discharge of the interface, facilitating the formation of adsorption layer over the iron surface. They also estimated the fractal dimension of the electrode surface in order to understand the nature of the electrode surface. DFT results clearly show that BBED possess corrosion inhibition properties by having a delocalization region (N1]C1]N2) in the benzimidazole ring that gives up its p

good yields.

**Structure**

**11**

**Metal/medium** Mild steel/1 M HCl N80 steel/15% HCl

N80 steel/15% HCl

Cu/1 M HNO3

[29]

[28]

[27]

*Corrosion Mitigation by Planar Benzimidazole Derivatives*

*DOI: http://dx.doi.org/10.5772/intechopen.92276*

**Reference**

[26]

*Corrosion Mitigation by Planar Benzimidazole Derivatives DOI: http://dx.doi.org/10.5772/intechopen.92276*

**Structure**

**10**

**Metal/medium** Mild steel/1 M HCl and 0.5 M H2SO4

Mild steel/1 M HCl Mild steel/1 M HCl Mild steel/1 M HCl

[25]

[23, 24]

[22]

**Reference**

[21]

**Structure**

**13**

**Metal/medium** Copper, zinc, brass/0.5 M NaCl

Zn/0.1 M HCl

> **Table 1.**

*The molecular structure of* 

*benzimidazole*

 *derivatives.*

[34]

*Corrosion Mitigation by Planar Benzimidazole Derivatives*

*DOI: http://dx.doi.org/10.5772/intechopen.92276*

**Reference**

[33]

#### *Corrosion Mitigation by Planar Benzimidazole Derivatives DOI: http://dx.doi.org/10.5772/intechopen.92276*

**Table 1.** *The molecular structure of benzimidazole*

 *derivatives.*

**Structure**

**12**

**Metal/medium**

Cu/0.02 M NaCl Cu and brass/0.4 M NaCl + 0.1 M NaOH

Cu/2 M HNO3

[32]

[31]

**Reference**

[30]

electron density through its HOMO orbital to the metal LUMO to form an adsorption layer over the metallic surface.

The influences of a benzimidazole derivative, namely, 1,8-bis(1-chlorobenzylbenzimidazolyl)-octane (CBO), on the corrosion behaviour of mild steel in different concentration HCl solutions was studied by Wang et al. [20]. The authors conclude that CBO acted as an excellent mixed-type inhibitor and strongly adsorbed via chemical bond formation. The data obtained from weight loss and electrochemical measurements have shown that the CBO has the excellent inhibiting properties for mild steel in HCl solution.

Ahamad and Quraishi [21] studied the corrosion inhibition effects of a watersoluble benzimidazole derivative, namely, bis(benzimidazol-2-yl)disulphide (BIMDS) on mild steel 1.0 M HCl and 0.5 M H2SO4. The results reveal that BIMDS showed a better performance in 0.5 M H2SO4 solutions than in 1.0 M HCl. Polarization measurements indicated that BIMDS is a mixed-type inhibitor in both acid media. The inhibitor obeyed the Langmuir adsorption isotherm model in both acid media.

Abboud et al. [22] studied the 2,2'-bis(benzimidazole) as a corrosion inhibitor for mild steel in 1 M HCl. The analysis of polarization curves showed that the mechanism of corrosion inhibition remains unchanged after the addition of the inhibitor and the inhibitor acts as a mixed type. The corrosion inhibition of the inhibitor can be interpreted by a simple blocked fraction of the electrode surface related to the adsorption of the inhibitor species according to a Langmuir isotherm on the steel surface.

configurations over the Fe (1 0 0) surface. **Figure 4** represents the equilibrium adsorption configurations of inhibitors on Fe (1 0 0) in the aqueous phase.

*Equilibrium configurations of ABI, BBIA and TBIA molecules.*

*Corrosion Mitigation by Planar Benzimidazole Derivatives*

*DOI: http://dx.doi.org/10.5772/intechopen.92276*

nomethyl)-1Hbenzo[d]imidazol-2-yl)phenol (MBP), 2-(1-((piperazine-1-yl) methyl)-1H-benzo[d]imidazol-2-yl)phenol (PzMBP), 2-(1-((piperidine-1-yl) methyl)-1H-benzo[d]imidazol-2-yl)phenol (PMBP), 4-(phenyl)-5-[(2-methyl-1Hbenzimidazol-1-yl)methyl]-4H-1,2,4-triazole-3-thiol (Inh I), 4-(4-methylphenyl)- 5-[(2-methyl-1H-benzimidazol-1-yl)methyl]-4H-1,2,4- triazole-3-thiol (Inh II) and 4-(4-methoxyphenyl)-5-[(2-methyl-1H-benzimidazol-1-yl)methyl]-4H-1,2,4 triazole-3-thiol (Inh III) on N80 steel in 15% HCl solution using weight loss measurement, potentiodynamic polarization and electrochemical impedance spectroscopy (EIS) techniques. They observed that inhibition efficiency of all the inhibitors increases with increase in concentration and decreases with increase in temperature. Furthermore the steel surface was analysed by SEM and AFM techniques. The density functional theory was employed for the theoretical evaluation of the studied inhibitors. **Figures 5** and **6** represent the AFM and SEM micrograph of the N80 steel

surface.

**Figure 4.**

method.

**15**

Yadav et al. [27, 28] group studied the corrosion inhibition of 2-(1-(morpholi-

The inhibitive actions of 2-mercaptobenzimidazole (MBI) and 2 thiobenzylbenzimidazole (TBBI) on copper corrosion in 1 M HNO3 medium were studied, using weight loss method, at 25–65°C and in the concentrations of the range of 5 <sup>10</sup><sup>5</sup> <sup>M</sup> to 10<sup>3</sup> M by Niamien et al. group in 2011 [29]. They reported the inhibition efficiencies of 90.0% for TBBI and 87.7% for MBI at 25°C. Negative values of changes in free energies indicate the spontaneous adsorption process with a combination of both physical and chemical processes. They have done the correlation between theoretical data and experimental results using DFT/B3LYP/6-31G (d,p)

Rao et al. [30] demonstrated the self-assembled (SAM) monolayer formation of 5-methoxy-2-(octadecylthio)benzimidazole (MOTBI) on fresh copper surface. The MOTBI SAM on copper surface was characterized by contact angle measurements, X-ray photoelectron spectroscopy and reflection absorption FTIR spectroscopy, and it is inferred that chemisorption of MOTBI on copper surface is through nitrogen. The corrosion protection ability of MOTBI SAM was evaluated in aqueous NaCl

solution using impedance, electrochemical quartz crystal nanobalance,

potentiodynamic polarization and weight loss studies.

Popova et al. and Mahdavian et al., respectively, in 2004 and 2010 studied the corrosion inhibition property of a series of benzimidazole derivatives [23, 24]. The results of Popova et al. reveal that the inhibition efficiency increased with the increase of organic substrate concentration, while the adsorption followed the Frumkin isotherm. They also suggest that there was no correlation observed among the studied various parameters of the electronic structure and the corrosion inhibition efficiency. Likewise Mahdavian results reveal that the studied inhibitor reduced both the cathodic and anodic polarization curves and behaved as a mixedtype inhibitor. The change in the values of the impedance parameters suggests the adsorption of the inhibitor on the metal surface. In surface analysis like SEM/EDX, the presence of sulphur confirmed the adsorption of the inhibitor on the mild steel surface.

Dutta et al. [25] in 2015 studied the corrosion inhibition of bis-benzimidazole type derivatives for mild steel with an immersion of 4 days in 1 M HCl. The results of the potentiodynamic polarization studies reveal that inhibitors produce a mixedtype protection but mostly affect the cathodic reaction.

#### *2.1.2 Computational results*

The approach of DFT results were used to probe into the interaction modes for the inhibitor molecules on the steel surface. The MDS was used to analyse the configuration of equilibrium adsorption of inhibitors. All the interaction energies between the inhibitors and the metal surface were deduced in the aqueous phase.

Cao et al. [26] performed the comparative theoretical study using DFT and MSD for 2-aminomethyl benzimidazole (ABI), bis(2-benzimidazolylmethyl) amine (BBIA) and tri-(2-benzimidazolylmethyl) amine (TBIA) on the mild steel surface. They concluded that the three-inhibitor molecules showed similar ability for the electron donation, while the difference in the electron-accepting ability makes them give a different inhibition performance. MD simulations suggest that the steric effect among the inhibitor molecular structures significantly affects the adsorptive

electron density through its HOMO orbital to the metal LUMO to form an adsorp-

The influences of a benzimidazole derivative, namely, 1,8-bis(1-chlorobenzylbenzimidazolyl)-octane (CBO), on the corrosion behaviour of mild steel in different concentration HCl solutions was studied by Wang et al. [20]. The authors conclude that CBO acted as an excellent mixed-type inhibitor and strongly adsorbed via chemical bond formation. The data obtained from weight loss and electrochemical measurements have shown that the CBO has the excellent inhibiting properties

Ahamad and Quraishi [21] studied the corrosion inhibition effects of a water-

Abboud et al. [22] studied the 2,2'-bis(benzimidazole) as a corrosion inhibitor for mild steel in 1 M HCl. The analysis of polarization curves showed that the mechanism of corrosion inhibition remains unchanged after the addition of the inhibitor and the inhibitor acts as a mixed type. The corrosion inhibition of the inhibitor can be interpreted by a simple blocked fraction of the electrode surface related to the adsorption of the inhibitor species according to a Langmuir isotherm

Popova et al. and Mahdavian et al., respectively, in 2004 and 2010 studied the corrosion inhibition property of a series of benzimidazole derivatives [23, 24]. The results of Popova et al. reveal that the inhibition efficiency increased with the increase of organic substrate concentration, while the adsorption followed the Frumkin isotherm. They also suggest that there was no correlation observed among the studied various parameters of the electronic structure and the corrosion inhibition efficiency. Likewise Mahdavian results reveal that the studied inhibitor reduced both the cathodic and anodic polarization curves and behaved as a mixedtype inhibitor. The change in the values of the impedance parameters suggests the adsorption of the inhibitor on the metal surface. In surface analysis like SEM/EDX, the presence of sulphur confirmed the adsorption of the inhibitor on the mild steel

Dutta et al. [25] in 2015 studied the corrosion inhibition of bis-benzimidazole type derivatives for mild steel with an immersion of 4 days in 1 M HCl. The results of the potentiodynamic polarization studies reveal that inhibitors produce a mixed-

The approach of DFT results were used to probe into the interaction modes for

the inhibitor molecules on the steel surface. The MDS was used to analyse the configuration of equilibrium adsorption of inhibitors. All the interaction energies between the inhibitors and the metal surface were deduced in the aqueous phase. Cao et al. [26] performed the comparative theoretical study using DFT and MSD

for 2-aminomethyl benzimidazole (ABI), bis(2-benzimidazolylmethyl) amine (BBIA) and tri-(2-benzimidazolylmethyl) amine (TBIA) on the mild steel surface. They concluded that the three-inhibitor molecules showed similar ability for the electron donation, while the difference in the electron-accepting ability makes them give a different inhibition performance. MD simulations suggest that the steric effect among the inhibitor molecular structures significantly affects the adsorptive

type protection but mostly affect the cathodic reaction.

soluble benzimidazole derivative, namely, bis(benzimidazol-2-yl)disulphide (BIMDS) on mild steel 1.0 M HCl and 0.5 M H2SO4. The results reveal that BIMDS showed a better performance in 0.5 M H2SO4 solutions than in 1.0 M HCl. Polarization measurements indicated that BIMDS is a mixed-type inhibitor in both acid media. The inhibitor obeyed the Langmuir adsorption isotherm model in both acid

tion layer over the metallic surface.

for mild steel in HCl solution.

media.

*Corrosion*

surface.

**14**

*2.1.2 Computational results*

on the steel surface.

**Figure 4.** *Equilibrium configurations of ABI, BBIA and TBIA molecules.*

configurations over the Fe (1 0 0) surface. **Figure 4** represents the equilibrium adsorption configurations of inhibitors on Fe (1 0 0) in the aqueous phase.

Yadav et al. [27, 28] group studied the corrosion inhibition of 2-(1-(morpholinomethyl)-1Hbenzo[d]imidazol-2-yl)phenol (MBP), 2-(1-((piperazine-1-yl) methyl)-1H-benzo[d]imidazol-2-yl)phenol (PzMBP), 2-(1-((piperidine-1-yl) methyl)-1H-benzo[d]imidazol-2-yl)phenol (PMBP), 4-(phenyl)-5-[(2-methyl-1Hbenzimidazol-1-yl)methyl]-4H-1,2,4-triazole-3-thiol (Inh I), 4-(4-methylphenyl)- 5-[(2-methyl-1H-benzimidazol-1-yl)methyl]-4H-1,2,4- triazole-3-thiol (Inh II) and 4-(4-methoxyphenyl)-5-[(2-methyl-1H-benzimidazol-1-yl)methyl]-4H-1,2,4 triazole-3-thiol (Inh III) on N80 steel in 15% HCl solution using weight loss measurement, potentiodynamic polarization and electrochemical impedance spectroscopy (EIS) techniques. They observed that inhibition efficiency of all the inhibitors increases with increase in concentration and decreases with increase in temperature. Furthermore the steel surface was analysed by SEM and AFM techniques. The density functional theory was employed for the theoretical evaluation of the studied inhibitors. **Figures 5** and **6** represent the AFM and SEM micrograph of the N80 steel surface.

The inhibitive actions of 2-mercaptobenzimidazole (MBI) and 2 thiobenzylbenzimidazole (TBBI) on copper corrosion in 1 M HNO3 medium were studied, using weight loss method, at 25–65°C and in the concentrations of the range of 5 <sup>10</sup><sup>5</sup> <sup>M</sup> to 10<sup>3</sup> M by Niamien et al. group in 2011 [29]. They reported the inhibition efficiencies of 90.0% for TBBI and 87.7% for MBI at 25°C. Negative values of changes in free energies indicate the spontaneous adsorption process with a combination of both physical and chemical processes. They have done the correlation between theoretical data and experimental results using DFT/B3LYP/6-31G (d,p) method.

Rao et al. [30] demonstrated the self-assembled (SAM) monolayer formation of 5-methoxy-2-(octadecylthio)benzimidazole (MOTBI) on fresh copper surface. The MOTBI SAM on copper surface was characterized by contact angle measurements, X-ray photoelectron spectroscopy and reflection absorption FTIR spectroscopy, and it is inferred that chemisorption of MOTBI on copper surface is through nitrogen. The corrosion protection ability of MOTBI SAM was evaluated in aqueous NaCl solution using impedance, electrochemical quartz crystal nanobalance, potentiodynamic polarization and weight loss studies.

In 2014, Özbay et al. [31] have carried out the inhibitive action of newly synthesized ortho-hydroxy Schiff bases of 5-amino-6-nitro-1H-benzimidazole against the corrosion of copper and brass in alkaline medium using potentiodynamic polarization and electrochemical impedance spectroscopy. The results showed an inhibi-

Madkour and Elsham [32] studied the inhibitive performance of seven synthesized 2-(2-benzimidazolyl)-4 (phenylazo) phenol (BPP\_1–7) derivatives which were investigated experimentally on the corrosion of copper in 2.0 M HNO3 acid using mass loss and thermometric and DC potentiodynamic polarization techniques. Quantum chemical calculations were investigated to correlate the electronic structure parameters of the investigated benzimidazole derivatives with their inhi-

Yanardag et al. [33] have studied the corrosion inhibition property of 1Hbenzimidazole, (BIM), 2-methyl-1H-benzimidazole (2-CH3BIM), 5-nitro-1Hbenzimidazole [5(6)-NO2BIM] and 5(6)-dinitrobenzimidazole (5,6-diNO2BIM) for copper, zinc and brass in alkaline and neutral media. The results under the experimental conditions suggest the efficiency order of the inhibitors is BIM > 5(6)- NO2BIM > 5,6-diNO2BIM > 2-CH3BIM in alkaline media (pH: 13) and 2-

The corrosion inhibition characteristics of 2-mercaptobenzimidazole (MBI), 2 mercapto benzimidazolyl-ethyl acetate (MBEA), 2-hydroxy benzimidazole (HBI)

hydrochloric acid were investigated by weight loss and potentiodynamic polarization techniques by the group of Shanbhag et al. [34]. The inhibition efficiency

and 2-hydroxy 5-nitro benzimidazole (HNBI) on zinc corrosion in 0.1 M

*Simulation models of H3O<sup>+</sup> (shown in CPK) in various inhibitor films (shown in line): (a) 2-SH-BI,*

tion efficiency of 91.0% and 97.4% for copper and brass, respectively.

*Corrosion Mitigation by Planar Benzimidazole Derivatives*

*DOI: http://dx.doi.org/10.5772/intechopen.92276*

CH3BIM > 5(6)-NO2BIM > BIM in the 0.5 M NaCl solution.

bition efficiencies values.

**Figure 7.**

**17**

*(b) 2-NH2-BI, (c) 2-CH3-BI and (d) BI.*

**Figure 5.** *AFM micrograph (a) without inhibitor, (b) with PzMBP, (c) with MBP and (d) with PMBP.*

*Corrosion Mitigation by Planar Benzimidazole Derivatives DOI: http://dx.doi.org/10.5772/intechopen.92276*

In 2014, Özbay et al. [31] have carried out the inhibitive action of newly synthesized ortho-hydroxy Schiff bases of 5-amino-6-nitro-1H-benzimidazole against the corrosion of copper and brass in alkaline medium using potentiodynamic polarization and electrochemical impedance spectroscopy. The results showed an inhibition efficiency of 91.0% and 97.4% for copper and brass, respectively.

Madkour and Elsham [32] studied the inhibitive performance of seven synthesized 2-(2-benzimidazolyl)-4 (phenylazo) phenol (BPP\_1–7) derivatives which were investigated experimentally on the corrosion of copper in 2.0 M HNO3 acid using mass loss and thermometric and DC potentiodynamic polarization techniques. Quantum chemical calculations were investigated to correlate the electronic structure parameters of the investigated benzimidazole derivatives with their inhibition efficiencies values.

Yanardag et al. [33] have studied the corrosion inhibition property of 1Hbenzimidazole, (BIM), 2-methyl-1H-benzimidazole (2-CH3BIM), 5-nitro-1Hbenzimidazole [5(6)-NO2BIM] and 5(6)-dinitrobenzimidazole (5,6-diNO2BIM) for copper, zinc and brass in alkaline and neutral media. The results under the experimental conditions suggest the efficiency order of the inhibitors is BIM > 5(6)- NO2BIM > 5,6-diNO2BIM > 2-CH3BIM in alkaline media (pH: 13) and 2- CH3BIM > 5(6)-NO2BIM > BIM in the 0.5 M NaCl solution.

The corrosion inhibition characteristics of 2-mercaptobenzimidazole (MBI), 2 mercapto benzimidazolyl-ethyl acetate (MBEA), 2-hydroxy benzimidazole (HBI) and 2-hydroxy 5-nitro benzimidazole (HNBI) on zinc corrosion in 0.1 M hydrochloric acid were investigated by weight loss and potentiodynamic polarization techniques by the group of Shanbhag et al. [34]. The inhibition efficiency

**Figure 7.** *Simulation models of H3O<sup>+</sup> (shown in CPK) in various inhibitor films (shown in line): (a) 2-SH-BI, (b) 2-NH2-BI, (c) 2-CH3-BI and (d) BI.*

**Figure 6.**

**16**

**Figure 5.**

*Corrosion*

*SEM micrograph (a) without inhibitor (b) Inh III, (c) Inh II and (d) Inh I.*

*AFM micrograph (a) without inhibitor, (b) with PzMBP, (c) with MBP and (d) with PMBP.*

increased with an increase in inhibitor concentration but decreased with an increase in temperature. The adsorption of MBI and MBEA obeyed Langmuir's adsorption isotherm, but HBI and HNBI followed Temkin's adsorption isotherm. The existence of inhibitor film on metal surface was established by scanning electron microscopy (SEM) images.

superior inhibition as compared to DMI and MMI, and the adsorption of these molecules on the metal surface affected both anodic and cathodic reactions. The three studied compounds can significantly reduce the corrosion current density values, and they exhibit mixed-type inhibition characteristics. The values of corro-

*Corrosion Mitigation by Planar Benzimidazole Derivatives*

*DOI: http://dx.doi.org/10.5772/intechopen.92276*

sion current density (icorr) without addition inhibitors are 104.4 μA cm<sup>2</sup>

21.5 μA cm<sup>2</sup> (MMI).

**Acknowledgements**

financial assistance.

**Author details**

Ambrish Singh<sup>1</sup>

Sichuan, China

China

**19**

Savas Kaya<sup>3</sup>

\*, Kashif R. Ansari<sup>2</sup>

, Hua Yu<sup>4</sup> and Yuanhua Lin1

**3. Conclusion**

addition of inhibitors reduced it to 5.5 μA cm<sup>2</sup> (TMI), 13.2 μA cm<sup>2</sup> (DMI) and

The book chapter gives an overview of the role of benzimidazole and their derivatives in the corrosion mitigation of industrially important alloys such as mild steel, N80 steel, aluminium, zinc, copper and brass in various aggressive media. Here we have also tried to explore the molecular structure, synthesis protocol and some important biological activity of benzimidazole derivatives. In view of the literature analysis, it could be concluded that benzimidazole derivatives have the potential ability to act as a suitable additive for various corrosive solutions.

The author Dr. Ambrish Singh is thankful to the Sichuan 1000 Talent Fund and the National Natural Science Foundation of China (No. 51274170) for providing

, Dheeraj S. Chauhan<sup>2</sup>

1 School of New Energy and Materials, Southwest Petroleum University, Chengdu,

4 Institute of Photovoltaics, Southwest Petroleum University, Chengdu, Sichuan,

© 2020 The Author(s). Licensee IntechOpen. This chapter is distributed under the terms of the Creative Commons Attribution License (http://creativecommons.org/licenses/ by/3.0), which permits unrestricted use, distribution, and reproduction in any medium,

2 Centre of Research Excellence in Corrosion, Research Institute, King Fahd

University of Petroleum and Minerals, Dhahran, Saudi Arabia

\*Address all correspondence to: vishisingh4uall@gmail.com

provided the original work is properly cited.

3 Department of Chemistry, Sivas Cumhuriyet University, Turkey

, Mumtaz A. Quraishi<sup>2</sup>

,

, and the

Zhang et al. [35] studied the diffusion of corrosive particles inside inhibitor films consisting of 2-mercaptobenzimidazole (2-SH-BI), 2-aminobenzimidazole (2-NH2- BI), 2-methylbenzimidazole (2-CH3-BI) and benzimidazole using molecular dynamics simulation (MDS). Diffusion coefficients of various corrosive particles in the films were calculated, and their order is 2-SH-BI < 2-NH2-BI < 2-CH3-BI < BI. Fractional free volume, interaction between corrosive particles and films and mobility of films were also investigated to illustrate the microscopic diffusion mechanism. As a result, it can be inferred that the order of inhibition efficiency is 2-SH-BI > 2-NH2-BI > 2-CH3-BI > BI. The simulation models of H3O<sup>+</sup> in various inhibitor films are shown in **Figure 7**.

Recently Singh et al. [36] have studied the corrosion inhibition effect of three synthesized benzimidazole derivatives, namely, 2-(3,4,5-trimethoxyphenyl)-1Hbenzo[d] imidazole (TMI), 2-(3,4-dimethoxyphenyl)-1H-benzo[d] imidazole (DMI) and 2-(4-methoxyphenyl)-1H-benzo[d] imidazole (MMI), for J55 steel saturated with CO2 in a 3.5% NaCl solution. The author has analysed the corrosion inhibition property using weight loss, impedance spectroscopy (EIS) and potentiodynamic polarization methods. The metal surface was examined by scanning electron microscope (SEM) and X-ray photoelectron spectroscopy (XPS). They have justified the experimental results using the DFT and MD studies. Their investigations both by experimental and theoretical analyses suggest that as the number of methoxy groups increases, the corrosion protection ability of the inhibitors increases, and thus TMI is the best inhibitor. The results of the Tafel curves are presented in **Figure 8**. As observed from the curves, inhibitor TMI exhibited a

**Figure 8.** *Tafel curves in without and with different concentrations of inhibitors: (a) TMI; (b) DMI; (c) MMI.*

*Corrosion Mitigation by Planar Benzimidazole Derivatives DOI: http://dx.doi.org/10.5772/intechopen.92276*

superior inhibition as compared to DMI and MMI, and the adsorption of these molecules on the metal surface affected both anodic and cathodic reactions. The three studied compounds can significantly reduce the corrosion current density values, and they exhibit mixed-type inhibition characteristics. The values of corrosion current density (icorr) without addition inhibitors are 104.4 μA cm<sup>2</sup> , and the addition of inhibitors reduced it to 5.5 μA cm<sup>2</sup> (TMI), 13.2 μA cm<sup>2</sup> (DMI) and 21.5 μA cm<sup>2</sup> (MMI).

#### **3. Conclusion**

increased with an increase in inhibitor concentration but decreased with an increase in temperature. The adsorption of MBI and MBEA obeyed Langmuir's adsorption isotherm, but HBI and HNBI followed Temkin's adsorption isotherm. The existence of inhibitor film on metal surface was established by scanning electron microscopy

Zhang et al. [35] studied the diffusion of corrosive particles inside inhibitor films consisting of 2-mercaptobenzimidazole (2-SH-BI), 2-aminobenzimidazole (2-NH2- BI), 2-methylbenzimidazole (2-CH3-BI) and benzimidazole using molecular dynamics simulation (MDS). Diffusion coefficients of various corrosive particles in the films were calculated, and their order is 2-SH-BI < 2-NH2-BI < 2-CH3-BI < BI. Fractional free volume, interaction between corrosive particles and films and mobility of films were also investigated to illustrate the microscopic diffusion mechanism. As a result, it can be inferred that the order of inhibition efficiency is 2-SH-BI > 2-NH2-BI > 2-CH3-BI > BI. The simulation models of H3O<sup>+</sup> in various

Recently Singh et al. [36] have studied the corrosion inhibition effect of three synthesized benzimidazole derivatives, namely, 2-(3,4,5-trimethoxyphenyl)-1Hbenzo[d] imidazole (TMI), 2-(3,4-dimethoxyphenyl)-1H-benzo[d] imidazole (DMI) and 2-(4-methoxyphenyl)-1H-benzo[d] imidazole (MMI), for J55 steel saturated with CO2 in a 3.5% NaCl solution. The author has analysed the corrosion inhibition property using weight loss, impedance spectroscopy (EIS) and

potentiodynamic polarization methods. The metal surface was examined by scanning electron microscope (SEM) and X-ray photoelectron spectroscopy (XPS). They have justified the experimental results using the DFT and MD studies. Their investigations both by experimental and theoretical analyses suggest that as the number of methoxy groups increases, the corrosion protection ability of the inhibitors increases, and thus TMI is the best inhibitor. The results of the Tafel curves are presented in **Figure 8**. As observed from the curves, inhibitor TMI exhibited a

*Tafel curves in without and with different concentrations of inhibitors: (a) TMI; (b) DMI; (c) MMI.*

(SEM) images.

*Corrosion*

**Figure 8.**

**18**

inhibitor films are shown in **Figure 7**.

The book chapter gives an overview of the role of benzimidazole and their derivatives in the corrosion mitigation of industrially important alloys such as mild steel, N80 steel, aluminium, zinc, copper and brass in various aggressive media. Here we have also tried to explore the molecular structure, synthesis protocol and some important biological activity of benzimidazole derivatives. In view of the literature analysis, it could be concluded that benzimidazole derivatives have the potential ability to act as a suitable additive for various corrosive solutions.

#### **Acknowledgements**

The author Dr. Ambrish Singh is thankful to the Sichuan 1000 Talent Fund and the National Natural Science Foundation of China (No. 51274170) for providing financial assistance.

#### **Author details**

Ambrish Singh<sup>1</sup> \*, Kashif R. Ansari<sup>2</sup> , Dheeraj S. Chauhan<sup>2</sup> , Mumtaz A. Quraishi<sup>2</sup> , Savas Kaya<sup>3</sup> , Hua Yu<sup>4</sup> and Yuanhua Lin1

1 School of New Energy and Materials, Southwest Petroleum University, Chengdu, Sichuan, China

2 Centre of Research Excellence in Corrosion, Research Institute, King Fahd University of Petroleum and Minerals, Dhahran, Saudi Arabia

3 Department of Chemistry, Sivas Cumhuriyet University, Turkey

4 Institute of Photovoltaics, Southwest Petroleum University, Chengdu, Sichuan, China

\*Address all correspondence to: vishisingh4uall@gmail.com

© 2020 The Author(s). Licensee IntechOpen. This chapter is distributed under the terms of the Creative Commons Attribution License (http://creativecommons.org/licenses/ by/3.0), which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.

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**23**

as additives.

mental properties:

characteristics of the latter

**Chapter 2**

*Said Abbout*

of *Ceratonia siliqua* L. seeds.

**1. Introduction**

polarization and impedance measurements

flexible means of corrosion prevention and mitigation [1].

**2.1 Definition and functions necessary in the corrosion inhibitor**

**2. Generalities about the corrosion inhibitors**

**Abstract**

Green Inhibitors to Reduce the

Over the last years, corrosion phenomenon is an important economical and lives lost, which calls in the last decades researches on its final resolution by various techniques. Through this book chapter, we present one of the most used methods to protect the metals: the corrosion inhibitor. We have presented the classification (liquid and gas phase), action mode (adsorption, barrier, reinforcing of the oxide layer, passivation, and formed insoluble complex), the application fields (water treatment, petroleum industry), and some particular inhibitors. In addition, we present a case study using a green corrosion inhibitor (GCI) prepared from the oil

**Keywords:** corrosion inhibitor, volatile corrosion inhibitors, *Ceratonia siliqua* L.,

Corrosion is an unstoppable phenomenon, in order to avoid or reduce the corrosion of metallic materials; the corrosion inhibitor is one of the most effective and

According to ISO 8044, the corrosion inhibitor is a chemical substance added to the corrosion system at a concentration chosen for its effectiveness; this causes a decrease in the corrosion rate of the metal without significantly modifying the concentration of any corrosive agent contained in the aggressive medium [2]. In addition, this role can be assured by other ways such as modification of the pH and incorporation of some metals like zinc in the chemical composition of the materials. In fact, such a definition cannot be perfect; however, it avoids to consider inhibitors

From this definition, a corrosion inhibitor must therefore verify some funda-

• Decreasing the corrosion rate of the metal while retaining the physicochemical

Corrosion Damage

#### **Chapter 2**

[30] Rao BVA, Iqbal MY, Sreedhar B. Electrochemical and surface analytical studies of the self-assembled monolayer

of 5-methoxy-2-(octadecylthio) benzimidazole in corrosion protection of copper. Electrochimica Acta. 2011;**55**:

[31] Özbay S, Yanardağ T, Dinçer S, Aksüt AA. Benzimidazole Schiff bases as corrosion inhibitors for copper and brass. European International Journal of Science and Technology. 2014;**3**:1-6

[32] Madkour LH, Elshamy IH.

Chemistry. 2016;**7**:195-221

Chemistry. 2012;**24**:47-52

**49**:587-590

1331-1336

**22**

[33] Yanardag T, Özbay S, Dincer S, Aksut AA. Corrosion inhibition efficiency of benzimidazole and benzimidazole derivatives for zinc, copper and brass. Asian Journal of

[34] Shanbhag AV, Venkatesha TV, Praveen BM. Benzimidazole derivatives as corrosion inhibitors for zinc in acid solution. Protection of Metals and Physical Chemistry of Surfaces. 2013;

[35] Zhang J, Yu W, Yu L, Yan Y, Qiao G, Hu S, et al. Molecular dynamics

simulation of corrosive particle diffusion in benzimidazole inhibitor films. Corrosion Science. 2011;**53**:

density functional theory, and molecular dynamic simulation.

[36] Singh A, Ansari KR, Quraishi MA, Lgaz H. Effect of electron donating functional groups on corrosion inhibition of J55 steel in a sweet corrosive environment: Experimental,

Materials 2019:**12**(1):17. Available from: https://doi.org/10.3390/ma12010017

Experimental and computational studies on the inhibition performances of benzimidazole and its derivatives for the corrosion of copper in nitric acid. International Journal of Industrial

620-631

*Corrosion*
